If $$a:b=3:2$$​, then $$(7a+9b):(5a+7b)=$$​ ?

Correct option is A

Given:

a : b = 3 : 2

We need to find (7a + 9b) : (5a + 7b).

Solution:

The ratio a : b = 3 : 2 can be expressed as a = 3k and b = 2k, where k is a constant.

Substitute a = 3k and b = 2k into the given expressions:

7a + 9b = 7(3k) + 9(2k) = 21k + 18k = 39k

5a + 7b = 5(3k) + 7(2k) = 15k + 14k = 29k

(7a + 9b) : (5a + 7b) =$$\frac{39k}{29k} = \frac{39}{29}$$ 

Thus, the required ratio is 39:29.